Chemistry A

chemistry

the study of the structure, properties, and composition of substances and the changes they undergo

organic chemistry

the study of compounds that contain the element carbon

inorganic chemistry

primarily the study of substances that do not contain carbon

analytical chemistry

the study of the composition of substances

physical chemistry

the study of the theoretical basis of chemical behavior, relying on math and physics

biochemistry

the study of the compostion and behavior of substances in living organisms

scientific method

method of inquiry involving observation, experiments, hypothesis and broad explanations called theories

observation

information obtained through the senses. observation in science often involves a measurement

hypothesis

a proposed explanation for observations

experiment

carfully controlled repeatable procedure for gathering data to test a hypothesis

theory

a thoroughtly test model that explains why experiments give certain results

scientific law

a concise statement that summarizes the results of many observations and experiments

qualitive measurements

a measurement that gives descriptive, nonnumeric results

quantitive measurement

a measurement that gives definite, usually numeric results

accuracy

the closeness of a measurement to the truth value of what is being measured

precision

describes the closeness, or reproducibility of a set measurement taken under the same conditions

accepted value

a quantity used by general agreement of the scientific community

experimental value

the quantitive value measured during an experiment

error

the difference between the accepted value and the experimental value

percent error

the percent that a measured value differs from the accepted value

International System of Units (SI)

the revised version of the metric system adopted by international agreement in 1960

meter

the base unit by length in SI

volume

the space occupied by a sample of matter

liter (L)

the volume of a cube measuring 10 cm on each edge (1000cm cubed) It is the common unprefixed unit of volume in the metric system.

weight

force that measures the pull of gravity on a given mass

kilogram (Kg)

the mass of 1L of water at 4 degrees C, it is the base unit of mass in SI

gram (g)

a metric mass unit equal to the mass of 1 cm cubed of water at 4 degrees C

temperature

a measure of the average kinetic energy of particles in matter. Temp determines the direction of heat transfer.

celsius scale

the temperature scale of which the freezing point of water is 0 degrees C and the boiling point is 100 degrees C.

Kelvin Scale

the temperature scale in which the freezing point of water is 273K and the boiling point is 373K. 0K is absolute zero.

Absolute Zero

the zero point on the Kelvin temp scale equivalent to -273 degrees C, all molecular motion theoretically stops at this temperature.